By Dave Elliott
“There is no habitat that benefits from coal pollution”, says David Roberts, commenting on an article in New Yorker last year by Jonathan Franzen, who was worried that, in the rush to deal with climate change by using renewables, local impacts on birds would get ignored, given the argument that global climate change due to fossil fuel use would hurt them much more than wind farms or whatever: http://grist.org/living/jonathan-franzen-is-confused-about-climate-change-but-then-lots-of-people-are/
By Dave Elliott
It has been an eventful year for renewables. While progress continues apace, with renewables now supplying around 15% of electricity in the UK and 22% of global electricity, in this pre- Xmas post, rather than spelling out all the good news, I will look at some of the less good stories from the year- concerning wind power and CSP. (more…)
Wind farms can reduce local bird numbers by up to half, according to a new study by the Royal Society for the Protection of Birds in conjunction with the Scottish Natural Heritage. It looked at 12 upland wind farms in the UK during the breeding season for a dozen common species including rare species such as hen harriers and skylarks. The research, published in the Journal of Applied Ecology, found 7 species showed ‘significantly lower frequencies of occurrence close to the turbines.’ The breeding population of buzzard, hen harrier, golden plover, snipe, curlew, wheatear and meadow pipit were reduced by up to half within 500 m of the turbines. It suggested that the most likely cause of the decline is the fact that birds are less likely to live and breed near wind farms because of the noise and development. Collisions with turbines was also suggested as a possible cause, but was thought to be less likely.
The British Wind Energy Association concurred with that: “This study shows there is a potential problem with displacement, but it is not yet proved that there is a problem with bird mortality rates.” It added ‘Wind farms and turbines are the most benign form of energy generation and the industry has found that wind farms simply do not pose a threat if they are properly sited and follow procedure. The threat of global warming could be a far greater threat to the population of birds than wind farms’.
The RSPB have recently backed wind farms as long as they are properly sited, and recommended a spatial planning approach as used elsewhere in the EU.
The Daily Telegraph (26/9/09) however claimed that RSPBs pro-wind stance had caused ‘many members to leave in protest because of concern about the developments ruining the view in remote areas and contributing to the decline of birds’.
Nevertheless, James Pearce-Higgins, senior conservation scientist with RSPB Scotland and lead author of the study, told them that it still supported wind farms. But developments should not be put in the wrong area – where they can harm birds. ‘There is an urgent need to combat climate change, and renewable energy sources, such as wind farms, will play an important part in this. However, it is also important to fully understand the consequences of such development, to ensure that they are properly planned and sited. Our results emphasise the need for wind farms to avoid areas with high densities of potentially vulnerable species such as curlews and golden plover, and help offer a way forward by informing the likely extent of positive habitat management which may help to offset the impacts of development.’
It’s not just birds though, it’s also bats that can have problems and it seems in larger numbers. But researchers at Aberdeen University, funded by the People’s Trust for Endangered Species (ptes.org) are currently making good progress on using radar to deter bats from colliding with in the turbine blades.
But collisions may not actually be the problem. A study of bat deaths at a local wind farm by the University of Calgary reported by Science Daily found that the majority of migratory bats in this location were killed because a sudden drop in air pressure near the blades caused injuries to the bats’ lungs known as barotrauma. Although the respiratory systems in birds can withstand such drops, the physiology of bats’ lungs does not allow for the sudden change of pressure.
TransAlta, Canada’s largest publicly traded provider of renewable energy, initiated a follow-up study at the same site to determine what could be done. They tested a revised operating procedure slowing turbine blades to near motionless in low-wind periods significantly reduces bat mortality. Prof. Robert Barclay, who led the University of Calagary study, commented “Biologically, this makes sense as bats are more likely to fly when wind speeds are relatively low.” It was found to reduce bat deaths from wind turbines by up to 60% without significantly reducing the energy generated from the wind farm.
Ref: Baerwald et al. 2009 ‘A Large-Scale Mitigation Experiment to Reduce Bat Fatalities at Wind Energy Facilities’. Journal of Wildlife Management 73 7 ; 1077 DOI: 10.2193/2008-233